Screen for paper pulp or the like



Dec. 23, 1 4. 1,520,371

J. M. SPANGENBERG SCREEN FOR PAPER PULP OR THE LIKE Filed Aug. 2, 1923 GUM;

Patented Dec. 23, 1924.

JOHN MAGNUS LARSSON' SPANGENBERG, OF FORSHAGA, SWEDEN.

SCREEN FOR PAPER PULP 0R LIKE.

Application filed August 2, 1923. Serial No. 655,154.

To all whom it may concern:

Be it known that I, JOHN MAGNUS LARS- SON SPANGENBERG, engineer, subject of the King of Sweden, residing at Forshaga, in the Kingdom of Sweden, have invented certain new and useful Improvements in Screens for Paper Pulp or the like; and I do hereby declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same.

The present invention relates to screens for paper pulp or the like which consist of a drum provided with perforated walls, and rotating in a vat, the interior of said drum communicating with a suitably arranged outlet and intake respectively. Surrounding said drum are movable members for alternating the direction of the fluid flowing through the screen in order to release said i screen or perforated wall from clogging fibres or the like.

The object of my invention is a particular arrangement of the member or members causing the fluid to alternate its direction when streaming through said screen.

An illustrative embodiment of my invention is shown diagrammatically in the accompanying drawing in which Figure l is a. vertical transverse section of a screening apparatus according to my invention and Fig. 2 shows a part of the same in plan view.

As the arrangements for supplying and discharging the pulp stock and for rotating the drum do not form objects of the present invention, but may be of any well known design, I do not consider an illustration of the same necessary.

On the drawing l-is the drum arranged in a well known manner to rotate in a vat 2. The cylindrical walls of said drum form a screen, for instance consisting of a perforated plate or a wire web, and 3 is the movable member or members adapted to cause an alternation of the streaming direction of the fluid through the screen plate or the perforated walls or mantle of the drum 1. According to the embodiment shown in the drawing said member is divided longitudinally into or is composed of several portions, each shaped as a plate or casing curved cylindrically and surrounding, as may be seen from the drawing, the

main part of the drum 1 (or it may surround said drum entirely) and located at a suitable distance from the drum for the purpose aimed at.

The members 3 are carried by arms 9 or the like located on each side of said drum, the top ends of said arms 9 being carried by eccentrics 7 arranged on the shafts 4. The ends of said shafts are provided with conical gearings 10 being in engagement with gearings 10 arranged on the ends of the shaft 5 in such a way that the shafts 4 will rotate with the same speed and in the same direction. When rotating the shafts 4 and thus also the eccentrics 7 the arms 9 and the stirring members 3, carried by the said arms 9, will move in such a way that each point of the members 3 will move along a circularpath in conformity with the eccentricity of the eccentrics 7 arranged on the shafts 4 so as to cause difierent parts of the members 3 successively to approach or to withdraw from the drum 1. By this fact every point of the screen operated by the motion of the members 3 will participate in the screening action, that is to say, the screening eflect will be as uniform as possible at different portions of the part of the drum acted upon by the members 3.

In screens hitherto in use which are pro- .vided with agitators outside the walls of the screening drum, said agitators have a motion different in difierent points of the circumference of said screening walls. By this fact different parts of said screening walls will perform the screening operation in different ways, that is to say, with a different efficiency. V

Further the arrangement described above and those previously known present an es sential difference by the fact that, in the present case, the different points of the agitator have a rotary motion while screening apparatus, previously known, provided with agitators, outside the mantle, have agitators performing a simple reciprocating motion in relation to the walls of the drum.

6 is a spray pipe adapted to wash away from the walls any clogging material, which would obstruct the apertures or perforations of the screen.

The arrangement may be used as well in the case when the pulp stock passes through the screen perforations from outside and towards the interior as in the case, when it see passes from within and outwards. In the last mentioned case the spray pipe will, of course, be placed at the outside of the drum, the spray nozzles being directed down towards the same. The number of the agitators 3 may vary and the eccentrics provided for each agitator, when using more than one, may, as shown ,in Figure 2, be displacedin relat on to each other in such a way that the movement of the different agitators will be as nchronous in relation to each other, igure 2, or the eccentrics may also be'placed equally in relation to each other on the shaft 4:, i. e. in'sucli a way that all agitators move in the same Way at each point of time, i. e. synchronous.

It is evident that the eccentrics or the means operating the a itators may be subjected to various-modi cations and I do not limit my invention to the precise structure shown.

Having thus described my invention I declarethat what I claim is:

1. In a pulp screening apparatus a vat for pulp stock, a rotary screen within said vat, the interior of said screen communicating with outlets and intakes, a plurality of agitatorsjorming a movable mantle wholly or partly surrounding. said screen, and located at a proper distance from the screen, means for moving said agitators in such a way as to cause a reciprocating movement I of the fluid through the screening walls, and

so as to impart to the agitators such a motion that the various parts thereof are successive- I}; brought to approach and withdraw from t e screen, said agitators being separated from each other along transverse planes.

2. In a pulp screening apparatus a vat for pulp stock, a rotary screen within said vat, the interior of said screen communicating with outlets and intakes, a plurality of agitators forming a movable mantle wholly or partly surrounding said screen, and located at a proper distance from the screen,

means for moving said agitators in such a way as to cause a reciprocating movement of the fluid through the screening walls, and

-so as to impart to the agitators such a motion that the various parts thereof are successively brought to approach and withdraw from the screen, said agitators being separated from each other alon transverse planes and adjacent agitators icing acted upon by eccentrics in such a way that they have an asynchronous movement in relation to each other. 4

3. In a pulp screening apparatus ai'vat for .pulp stock, a rotary screen within said vat, the interior .of said screen communicating with outlets and intakes, a plurality of agitators forming a movable mantle wholly or partly surrounding said screen and located at a proper distance therefrom, means for imparting a rotary movement to said agitators so as to cause a'reciprocating movement of the fluid through the screening walls and so as to impart to the agitators a motion such that various parts thereof are successively brought to approach and withdraw from the screen, said agitators being separated from each other along a transverse plane.

4. In a pulp screening apparatus a vat for pulp stock, a rotary screen within said vat, the interior of said screen communicatin with outlets and intakes, a plurality of agitators forming a movable mantle wholly or partly surrounding said screen and located at a proper distance therefrom, means for moving said agitators in such a way as to cause a reciprocating movement of the fluid through the screening walls, and so as to impart to the agitators such a motion that the various partsthereof are successively brought to approach and withdraw from the screen, said agitators being separated from one another along transverse planes and adjacent agitators being actuated so that they have an asynchronous movement in relation to one another.

In testimony whereof I aifix my signature.

' JOHN MAGNUS LARSSON SPANGENBERG.

Witnesses:

A. IIAL ARTZ, ERIC NYLANDRE. 

